The present invention relates in general to an electrophotographic imaging apparatus, and more particularly to power supply configurations that allow the electrophotographic imaging apparatus to accommodate fusers having different voltage requirements.
In electrophotography, a latent image is created on an electrostatically charged photoconductive surface by exposing select portions of the surface to laser light. Essentially, the density of the electrostatic charge on the photoconductive surface is altered in areas exposed to a laser beam relative to those areas unexposed to the laser beam. The latent electrostatic image thus created is developed into a visible image by exposing the photoconductive surface to toner, which contains pigment components and thermoplastic components. When so exposed, the toner is attracted to the photoconductive surface in a manner that corresponds to the electrostatic density altered by the laser beam. The toner pattern is subsequently transferred from the photoconductive surface to the surface of a print medium, such as paper, which has been given an electrostatic charge opposite that of the toner.
A fuser then applies heat and pressure to the print medium before it is discharged from the apparatus. The heat causes constituents including the thermoplastic components of the toner to flow into the interstices between the fibers of the medium and the pressure promotes settling of the toner constituents in these voids. As the toner is cooled, it solidifies and adheres the image to the medium.
Many fusing applications require precise control over fuser temperatures to ensure that the toner adequately adheres to the print medium. To generate the appropriate temperatures, the fuser often includes a resistive heating device, such as a halogen lamp, that operates at the main supply voltage that powers the apparatus. Temperature is controlled by switching the power supply to the heating device on and off as necessary, e.g., using a triac or similar control device. Due at least in part to the resistive characteristics of the heating device, such fusers are typically designed to operate on narrow voltage ranges. However, the world has relatively large variations in power line standards. For example, line voltages typically range around 100 volts of alternating current (VAC) in Japan, about 110 VAC to 127 VAC, in the United States and about 220 VAC to 240 VAC in Europe.
As such, a manufacturer may be required to provide a different product version of an electrophotographic apparatus where the apparatus is to be used in geographic locations having different main power line standards. This makes supply chain planning complicated because demand for several apparatus configurations must be predicted, rather than only needing to predict aggregate demand. The different product versions further create the potential that a fuser intended for one voltage range of operation is installed in an apparatus that is configured for a second voltage of operation, which can cause improper operation of the apparatus.